This invention relates to thermal expansion valves, and in particular to thermal expansion valves in which the flow direction is reversible. In further particular, the invention relates to a thermal expansion valve body having universal outlet and bypass aperture protrusions such that the position of the outlet for the thermal expansion valve and the position of the bypass aperture of the thermal expansion valve can readily be switched when final formation takes place of the thermal expansion valve from the thermal expansion valve body.
Thermal expansion valves of the nature of the present invention are used in installations where the flow direction is reversible. For example, such valves are used in heat pump systems, where the flow direction is reversible so that the heat pump provides heating during cold weather and cooling during warm weather. There are generally two types of the thermal expansion valves, one in which the inlet and outlet of the thermal expansion valve are aligned in a straight line fashion, and another where the inlet and outlet are angled, normally at a right angle, to one another so that inlet and outlet flows are at an angle to one another. In the past, such valves have not been universalxe2x80x94two valve versions (and the resulting metal forging dies) are required for the two different thermal expansion valves.
Thermal expansion valves of the type of the present invention are disclosed in prior U.S. Pat. Nos. 4,852,364 and 5,251,459. In heat pump systems there are typically two expansion valves with bypass, being situated between an indoor coil and an outdoor coil. When the heat pump system operates in the heating mode cooled refrigerant leaves the indoor coil, bypasses the first expansion valve via the bypass, expands in the second expansion valve and evaporates in the outdoor coil. When the heat pump system is in the cooling mode the flow direction of the refrigerant is reversed and the refrigerant is condensed in the outdoor coil, and evaporates in the indoor coil. During the flow from indoor coil to outdoor coil the refrigerant bypasses the second expansion valve and is expanded by the second expansion valve. As is well known in the art, the thermal expansion valve includes an external or internal bypass which is utilized depending on the utilization of the thermal expansion valve in the heating cycle or the cooling cycle.
The invention is directed to a single thermal expansion valve body which can be used to create a thermal expansion valve, whether the inlet and outlet of the thermal expansion valve are aligned in a straight line fashion, or whether the inlet and the outlet are angled in relation to one another. The thermal expansion valve which is made from the thermal expansion valve body according to the invention includes an internal bypass, and further includes at least an inlet, an outlet, and a bypass aperture, with one of the outlet and the bypass aperture being aligned opposite the inlet and the other of the outlet and the bypass aperture being aligned at an angle to the inlet. The thermal expansion valve body includes a inlet protrusion for the inlet, an outlet protrusion for the outlet, and a bypass aperture protrusion for the bypass aperture. The outlet protrusion and the bypass aperture protrusion are substantially identical such that the outlet can be formed in either one of the outlet and bypass aperture protrusions and the bypass aperture can be formed in the other of the outlet and bypass aperture protrusions.
In accordance with the preferred form of the invention, the thermal expansion valve body also includes a pressure equalizing protrusion which can be used for formation of a pressure equalizing connection to the thermal expansion valve. Preferably, the pressure equalizing protrusion is opposite either the outlet protrusion or the bypass aperture protrusion.
Also in accordance with the preferred form of the invention, the outlet protrusion and the bypass aperture protrusion are aligned generally at an angle to one another, which angle is preferably a right angle. The outlet protrusion and the bypass aperture protrusion are located at equal distances from the top and bottom of the thermal expansion body.
Additionally, the outlet protrusion and the bypass aperture protrusion have substantially the same size, diameter, and height from the thermal expansion body. The protrusions are therefore the substantially identical, so that one or the other of the outlet and the bypass aperture can be formed in one or the other of the outlet and the bypass aperture protrusions.
By forming the thermal expansion valve body in accordance with the invention, only a single thermal expansion valve body need be provided, whether the ensuing thermal expansion valve has the inlet and outlet aligned opposite one another, or whether the inlet and the outlet are aligned at an angle to one another. Thus, the production expense of the thermal expansion valve is greatly reduced.